An inkjet recording head, which is a typical example of a recording head, generally includes a recording element substrate that ejects ink (liquid), an ink tank, which is a container for containing ink, and an electric wiring substrate that transmits ejection control signals and electric power for the ejection process to the recording element substrate. The recording element substrate is fixed to the ink tank that serves as a retaining member, and the electric wiring substrate is also fixed to the ink tank.
FIGS. 8A to 8C illustrate a structure according to the related art in which an electric wiring substrate H2000 is fixed by adhesion.
FIG. 8A illustrates an inkjet recording head viewed from the side of a recording element substrate H1000. In FIG. 8A, wires H2002 are shown in a see-through manner for explanation. FIG. 8B is a sectional view of FIG. 8A taken along line VIIIB-VIIIB. FIG. 8C is an enlarged view of part VIIIC in FIG. 8B.
As shown in FIG. 8A, the recording element substrate H1000 is disposed in an opening H2003 provided in the electric wiring substrate H2000. The electric wiring substrate H2000 and the recording element substrate H1000 are fixed to an ink tank H3000.
As shown in FIG. 8C, the electric wiring substrate H2000 has a layered structure including a first film H2010 composed of an insulator, a second film H2020 composed of an insulator, and a wiring layer H2030 including the wires H2002. The wires H2002 are connected to the recording element substrate H1000 at one end thereof, so that control signals and electric power can be transmitted from a main body in which the inkjet recording head is mounted to the recording element substrate H1000.
In general, the electric wiring substrate H2000 is fixed to the ink tank H3000 by an adhesive H4100, and an outer peripheral section of the electric wiring substrate H2000 is sealed by a sealant H4000 (Patent Literature 1).
However, according to the method of the related art in which the electric wiring substrate is fixed to the retaining member by applying the adhesive, there is a possibility that the adhesive cannot be applied to edge portions of the electric wiring substrate owing to, for example, uneven application of the adhesive.
As shown in FIG. 9A, there may be a case in which an edge portion of the electric wiring substrate is not fixed by the adhesive H4100 and therefore the edge portion of the electric wiring substrate H2000 is raised from the ink tank H3000. If the recording head is moved in this state in the recording operation, there is a possibility that the electric wiring substrate will come into contact with a recording medium P, such as a paper sheet, and become bent, as shown in FIG. 9B. In such a case, there is a risk that electric signals cannot be transmitted to the recording element substrate and the recording head cannot perform the ejecting function. In particular, the number of types of recording media has recently been increased, and there is a high possibility that the electric wiring substrate will be bent if a strong recording medium is used in a printing operation.